In the base DITA distribution, find the file "
concept.dtd" and copy it into the
faq-question/dtd directory and rename it "
faq-question.dtd" (in the sample materials this file is named
%concept-info-types;and rename it to
%faq-question-info-types;. Set its replacement text to "no-topic-nesting", rather than "%info-types;".
<no-topic-nesting>element is one of the DITA "specialization" element types that exist to work around limitations in DTD syntax. In particular, if you have a content model declared like so:
(%some-parameter-entity;)You cannot simply set
%some-parameter-entity;to an empty string, because the resolved result would be:
()which is not valid.
The solution is to define an empty element type that acts as a placeholder, thus
Try validating or opening the test document again. This time you should not get a "DTD not found" error but you should get "element type 'faq-question' not declared" sort of errors, indicating that it found the DTD but not the declarations for the FAQ-specific element types, which of course we haven't created yet. But we're making progress.